Distribution, use, trade and conservation of Paris polyphylla Sm. in Nepal

Paris polyphylla Sm. is an important perennial medicinal plant of the Himalayas that is increasingly being used in traditional medicines and pharmaceutical industries. To meet this accelerating demand, people are harvesting it at unsustainable rates and trading it across Nepal through both legal and illegal means. It is therefore imperative to understand the socio-ecological interactions regarding the current distribution, use, trade, and conservation of P. polyphylla, in order to guide its sustainable production in the future.In this study, we employed both qualitative and quantitative methodology to collect data from primary and secondary sources. We first carried out extensive field surveys and informal interviews with key stakeholders across 51 of the 77 districts in Nepal. In all we laid 696 quadrats each measuring 1 m × 1 m to understand the prevalence and distribution of P. polyphylla and held discussions in each district to collect information on the use, trade and conservation of P. polyphylla. We also reviewed over 150 studies pertaining to population and use of P. polyphylla, along with 18 years (2000–2017) of trade records of the species. We lastly modeled the species’ potential distribution using a maximum entropy (MaxEnt) with 310 ground control points and 20 predictive variables.In this study, we found P. polyphylla growing in all 51 districts, but were only able to find use records from 38 of these districts, and trade records from only 39 districts including 19 border districts. This pattern reveals that the production, collection, use and trade of P. polyphylla vary greatly across the country. Out model predicted a total of 51 mid-hill and mountainous districts as potential distribution areas of P. polyphylla, and this work shows that all of these districts except Surkhet and Mustang may be suitable for its growth in the future.We have found that the high demand for P. polyphylla has driven people to conduct harvests prematurely resulting in habitat degradation. Illegal trade due to weak database management and porous border has also impacted the sustainability of these harvesting practices and made P. polyphylla vulnerable to extinction. To meet the need of market demand and to maintain sustainable production, P. polyphylla should be conserved and cultivated in forests and fringe areas respectively to the extent of its potential distribution and have more stringent sustainable harvesting guidelines applied to its trade.